Mian-Chowla sequence

The Mian-Chowla sequence is a B2sequence with a1=1 and an for n>2 being the smallest integer such that each pairwise sum ai+aj is distinct, where 0<i<(n+1) and likewise for j, that is, 1≤i≤j≤n. The case i=j is always considered.

At the beginning, with a1, there is only one pairwise sum, 2. a2 can be 2 since the pairwise sums then are 2, 3 and 4. a3 can’t be 3 because then there would be the pairwise sums 1 + 3 = 2 + 2 = 4. Thus a3=4. The sequence, listed in A005282 of Sloane’s OEIS, continues 8, 13, 21, 31, 45, 66, 81, 97, 123, 148, 182, 204, 252, 290, 361, 401, 475, … If we define a1=0, the resulting sequence is the same except each term is one less.